Answer:
The claim made by the researcher lacks the validity on basis of reasons as indicated in the explanation.
Step-by-step explanation:
The claim made by the researcher is not valid on basis of following reasons:
- Interacting variables are not mapped accurately. The additional variables as the health status of the volunteers, eating and fitness habits are not considered in the consideration. This results in a in complete validation.
- The placebo effect is not catered accordingly. As the half of the volunteers are taking nothing, this is not the direct influence of the placebo and thus double-blinded testing for placebo effect is to be ensured in future experiments.
- The environmental effects are not considered as the effect under study is dependent on the environmental effects, thus the claim is biased and the generalization is not valid.
So the expression is:

You can combine like terms, which are terms that contain the same variables raised to the same power. That means you can combine the two

.

The other terms can't be combined.
Your final answer should be

.
Answer: 1 go to 1 the 2 go to 5 the 3 go to 3 the 4 go to 2 the 5 go to 4
Step-by-step explanation: i hop this helps if not sorry :(
B.Number of eye blinks in a minute.
We do not have a set amount of blinks per minute.
A.Inccorect,a touchdown is 6 points
C.Speed of a race car rises at a constant rate depending on the car,speed e.t.c
D.Dogs get placed in a kennel and have a set ammount.
D^2 - 4d = 3d
d^2 - 7d = 0
d(d - 7) = 0
d = 0 or d - 7 = 0
d = 0 or d = 7